The present invention relates to a pneumatic tire, more particularly to an arrangement of axial tread grooves suitable for a studless tire capable of providing good road grip on both of icy and snowy roads.
In recent years, various studless tires provided in the tread portion with a large number of sipes are widely used as winter tires suitable for running on well-paved roads in order to avoid dust pollution.
Such sipes can provide good road grip when running on relatively flat and hard road surfaces covered with icy and/or a water film. But, when running on road surfaces covered with a certain depth of snow, it is difficult for the sipes to provide good road grip.
If the grooved area (especially of axial grooves) in the tread portion is increased, on-the-snow grip may be improved, but tire performances, for example, maneuverability, grip, running stability and the like during running on the above-mentioned relatively flat and hard road surfaces are liable to deteriorate.